Size tunable synthesis of HDA and TOPO capped ZnSe nanoparticles via a facile aqueous/thermolysis hybrid solution route

We herein report the synthesis of hexadecylamine (HDA) and trioctylphosphine (TOPO) capped ZnSe nanoparticles (NPs) via a simple and environmentally benign aqueous/thermolysis hybrid solution route. The synthesis involves the use of cheap and less toxic precursors as starting materials. By varying the reaction temperature, monomer concentration, capping group and zinc precursor we systematically studied the size, optical and structural properties of the as-synthesised NPs. The NPs were characterised using UV–Vis absorption and photoluminescence spectroscopy, transmission electron microscopy, high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). All the particles exhibited strong quantum confinement with respect to the bulk ZnSe. The absorption and emission maxima of the TOPO-capped ZnSe NPs are blue-shifted, as compared to the HDA-capped NPs synthesized at the same temperature and monomer concentration. The use of Zn(CH₃COO)₂ as the precursor resulted in a smaller NPs with no evidence of trap emission. The HRTEM confirm the crystallinity of the material while the XRD results indicated that the capping group has no pronounced effect on the phase and crystalline structure of the as-synthesised ZnSe NPs.